The Mozilla Foundation has decided to add a new style to the Firefox preferences and options UI. It is already used by default in Firefox 36 beta, but you can also enable the new UI manually in the current fixed version of Firefox 35.
Let's see how you can open the new preferences page and what's different.
To enable the new preferences in Firefox 35, type the following address:
Press Enter and wait a few seconds (the first time will be delayed). It will open a window like the one you see in the picture below:
Unlike the dialog in the old settings, these preferences appear right in a tab. Settings are not organized into tabs by category, but are categorized by rows to the left.
The design reminds the Firefox add-ons manager. Apparently the Mozilla Foundation displays settings in this way to give a consistent look to all operating systems and devices.
If you use Google Chrome you will notice that its settings resemble the new Mozilla UI. This shows that the Mozilla Foundation is still copying the Google Chrome design. The new arrangements are slower than the old ones, however, they have certain advantages. For example, the search settings appear to be more comprehensive than the old ones.
It is noteworthy that its Nightly version Firefox has these preferences enabled by default.